I can see the reasoning behind no 3rd party software on the iPhone... there's security issues to worry about, and there's also issues of people writing inefficient apps that hog wireless bandwidth (which is limited per cell tower, I think, and also hurts AT&T's bottom line on unlimited data plans), as well as the issue of bricking peoples phones with bad software which is far more of a PITA than for a non-phone device (that hardware is linked to a phone number/account, etc). There's also the idea that they are protecting revenue for their partners by making sure that some new feature is only available as a paid-for service, not a free third party app.
On the touch though, if something screws up your iPod royally you can just do a software restore and resync it, problem solved. I'm assuming that Apple will make changes that could stop 3rd party software if they uncover a security issue which they then fix (which could break any loophole that people are using to get 3rd party apps to run). However, I'm hopeful that this
means we'll see someone write both a generic installer for iPod touch apps, as well as some sort of unofficial library for XCode to help other people develop touch applications.
I also wonder if, as some other people have drawn some connections, that this is sort of a test to see what people want out of the touch without having to develop or support things that could fail. If there's lots of people who end up creating and using applications for the touch, Apple could make money selling licenses for 'approved' iPod touch software and sell it through iTMS like the do for games.
Anyways, this makes me much, much more interest in the touch, and assuming that a decent 3rd party/homebrew software community springs up I'll get one once they hit the refurb store.
